The new generation mobile devices, such as smart phones, provide more and more enhanced computational functionalities via open network connections. Such mobile devices are e.g. capable of receiving e-mail, share software with one another through short-range connections, downloading and executing software from the Internet, making automated calls and act under remote control. Hence, similar to a personal computer, mobile devices and in particular the software components involved in the setting up of a connection between the mobile device to the network, are vulnerable to attacks of malicious software (malware).
Typically malware attempts to make misuse of mobile device or to simply disrupt legitimate use of a mobile device and to use of security flaws in the authentication procedure, usually referred to as an authentication and key agreement (AKA), which provides a subscriber access to a network. Nowadays are AKAs designed not only to authenticate the mobile device to the network, but also to authenticate the network to the mobile device. For example, the UMTS AKA uses a mutual authentication procedure wherein the mobile device has to authenticate itself to the Visitor Location Register (VLR) and the VLR has to authenticate itself to the mobile device. Well known AKAs and their associated security threats are described in 3GPP TR 33.900.
From this document it follows for example that the UMTS AKA is vulnerable to certain types of man-in-the-middle attacks, wherein a mobile device of an attacker may use authentication information such as the RES from the (U)SIM of the victim in order to obtain access to the network. Such a man-in-the-middle attack may result in the attacker accessing the network as if the connection was set up by the victim. As the network in such a situation cannot distinguish between a legitimate connection and a man-in-the-middle using malware on the victim's mobile device, the attacker is allowed to use services on the expenses of the victim thereby causing substantial damage.
Hence, there is a need in the art for improved methods and systems for authentication to a network.
KR 20100054191 describes a method to solve the possible synchronisation problem of authentication vectors (AV) between the Home Network and other service networks using a shared key and Time Stamps. The method involves including location information, the so-called Location Area Identity (LAI), in the computation of the Message Authentication Code (MAC) on various authentication messages and verifying the MACs on these messages. If a LAI is quite large, it is possible, however, that the attacker and the victim are in the same LAI, in which case the method of KR 20100054191 does not protect against the described attack. More importantly, if the mobile device is moving, after sending the registration request it may have ended up in a different LAI, in which case the verification method of KR 20100054191 fails, because the mobile device and the network carry out the computation of the MACs with different LAI values.
US 2008/182592 describes a method for obtaining location information from a mobile device in a secure way. The location information is generated at the mobile device and then either signed by the mobile device with a private key or incorporated in the messages of the normal authentication protocol. This patent application, however, does not contain a cross-check of the location information present at the network side and the location information present at the mobile device.